Definition - What does Maceration mean?
Maceration is a winemaking process whereby the color, flavor and tannins are transferred from the grape skins to the wine juice, aka must. Macerate literally means "to soften by soaking"; the grape skins are left to soak in their own juices so that they soften and release the qualities that give wines color, body, mouth-feel and the ability to age.
Red wines are allowed to macerate until fermentation is complete. This means that the wines are rich in color. Rosé wines are allowed to macerate for a short period of time, transferring only a little bit of color into the wine which gives it the soft, pink color. White wines are very rarely allowed to macerate. Only varieties with less natural flavor and body structure like Sauvignon Blanc and Semillon.
WineFrog explains Maceration
Maceration begins the moment grape skins a broken and exposed to heat; it can continue until well after fermentation is complete, depending on when the winemaker decides to separate the must from the skins. However, the winemaker stops it when they feel the wine has received all of the color, flavor and tannins needed for the wine style they are creating.
As the wine ferments, it releases carbon dioxide, pushing the skins to the surface of the mixture. This is called the cap. Winemakers push the cap down to force/encourage continued contact between the skin and juice. There are three ways for them to push the cap down:
- Classic stomping of grapes - called Pigeage - where the cap is pushed down by many feet stomping on the mixture
- Mechanical pressing
- Pneumatage process - air/gas is sequentially injected into the juice; bubbles cause the juice and skins to circulate, much like a hot tub for wine.
Carbonic maceration is the third type of maceration. It is most commonly used in Beaujolais for their Gamay wines. This method ferments the juice while it is still inside the grape, reducing the amount of time required to process the wine (about six weeks). However, this also reduces the aging ability of the wines - they become light, fruity and low in tannins.